Which modern element was called eka-aluminum by Dmitri Mendeleev?

The modern element that Dmitri Mendeleev referred to as eka-aluminum is gallium.12

In 1869, when Mendeleev published his periodic table, he left gaps for elements that had not yet been discovered and accurately predicted the properties of several of them, including eka-aluminum. When the French chemist Paul-Émile Lecoq de Boisbaudran discovered gallium in 1875, he found that its properties matched those Mendeleev had predicted for eka-aluminum. This successful prediction was a significant factor in the general scientific acceptance of the periodic table.312